1. Technical Field
The present invention relates to a projection apparatus, a projection state adjustment method, and a projection state adjustment program.
2. Related Art
Generally, a projector as an image projection apparatus is known, in which an image based on image data output from a personal computer, for example, is projected onto a projection target such as a screen.
Such a projector is sometimes used to project an image onto the curved surface of a circular cylinder, for example.
For example, in the case where an image with no distortion is appropriately projected onto a circular cylinder, it is necessary to apply geometric correction to a projected image.
Functions for use in such geometric correction are different depending on the positional relationship between the projector and the circular cylinder, such as the orientation of the projector relative to the circular cylinder, a distance from the projector to the circular cylinder, and the diameter of the circular cylinder.
Thus, it is necessary to provide the settings of geometric correction depending on the positional relationship between the projector and the circular cylinder, for example.
Some methods are known as a setting method for such geometric correction.
For example, a first method is a method in which a projector is used to project a grid pattern onto a circular cylinder, and a user adjusts the positions of intersection points of grids to sequentially change the set values of geometric correction.
A second method is a method in which a distance and a direction from a projector to a circular cylinder, the range of a screen on the circular cylinder, the angle of view of the projector, the position of an optical axis, and so on are found, and correction values necessary for geometric correction are calculated from the values.
For a third method, a technique is disclosed in JP-A-2004-320662, for example, in which typical geometric correction methods not directly involved in a circular cylinder are combined to adjust images.
As for the foregoing setting methods for geometric correction, according to the first method, for example, the user can intuitively perform manipulations.
However, it is necessary to adjust a large number of positions of intersection points, and it takes a lot of time and effort.
For example, in the second method, it is necessary to accurately determine the positional relationship between the projector and the circular cylinder, for example, which is usually difficult to determine, and it is difficult to implement the second method.
For example, according to the third method, the user can relatively easily perform manipulations because the amount of manipulations is small.
However, it is difficult for the user to intuitively grasp which geometric correction methods to combine.
Moreover, the first method and the third method provide approximate settings, and the methods do not always provide mathematically accurate correction.